Apparatus for stripping rolled tube blank from mandrel bar



' Sept. 1, 1959 W. A. LINDSTROM EIAL APPARATUS F`OR STRIPPING ROLLED TUBE BLANK FROM MANDREL BAR Filed Aug. 22, 1951 5 Sheets-Sheet l Sept l, 1959 w. A. LINDsTRoM ETAL 2,901,818

APPARATUS RoR STRIPPING ROLLED TUBE BLANK FROM MANDREL BAR Filed Aug. l22. 1951 l 3 Sheets-Sheet 2 hwenoj fm 7594 www0/1MM #4Q/@V4 5055596,

Sept. 1, 1959 DREI.. BAR

w. A.y LINDsTRoM ET AL APPARATUS FOR sTRIPPING ROLLED TUBE BLANK FROM MAN 5 Sheets-Sheet 3 Filed Aug. 22, 1951 United States Patent Oiiice 2,901,818 Patented Sept. 1, 1959 APPARATUS FOR STRIPPING ROLLED TUBE BLANK FROM MANDREL BAR Walter A. Lindstrom and Harry A. Solsberg, Gary, Ind.,

assignors to United States Steel Corporation, a corporation of New Jersey Application August 22, 1951, Serial No. 243,152 3 Claims. (Cl. 29-235) This invention relates to apparatus for removing a tube yblank from a mandrel b-ar on which it is rolled, in the process of making pipe referred to as rolling on a bar.

After a tube blank has been rolled to the desired extent on a bar, it is essential to remove the bar from the blank as quickly as possible to prevent the blank from shrinking tight on the bar as a result of cooling. This has been accomplished heretofore lby pulling the bar through a hole in a stripper plate which is large enough for the bar but too small to admit the tube. Such practice, however, frequently results in the extrusion of thin tins of the metal of the tube into the clearance between the hole and the bar, which interfere with sidewise delivery of the tube as is `sometimes desirable. It is accordingly the object of our invention to provide a sectional stripper plate and means for moving at least one portion thereof to permit sidewise delivery of the blank regardless of the presence of lins extruded into the opening in the plate.

A further object is to provide a stripper apparatus having a guide for insuring proper entry of the leading end of the bar into the hole in the stripper plate.

A still further object is to provide control means of exceptionally rugged character for causing operation in proper sequence of a traction conveyor for pulling the bar from the tube blank, the means for retracting a portion of the stripper plate and means for causing sidewise delivery of the tube when stripped from the bar.

In a preferred embodiment of the invention, we provide a split conical entry guide with power means to move one portion from and toward the other, and a split stripper plate having one portion mounted in each portion of the guide. A motor-driven chain conveyor having means to engage the end of a bar projecting through the guide and stripper plate, is controlled by a switch operated by a target in the path of a bar advancing through the hole in 'the plate. The target is counterbalanced so as to restore the switch on passage of the bar therebeyond. This causes the power means to open the guide and stripper plate and also starts separate power means for delivering the pipe sidewise.

A complete understanding of the invention may be obtained from the following detailed description and explanation which refer to the accompanying drawings illustrating the present preferred embodiment. In the drawings:

Figure l is a diagrammatic plan View showing the invention as installed adjacent a continuous mandrel mill;

Figure 2 is a plan view of the entry guide, target and the adjacent end o-f the chain conveyor;

Figure 3 is a longitudinal section taken along the plane of line III-HI of Figure 2;

Figure 4 is an elevational of the ating mechanism;

Figure 5 is a partial cross section paratus for delivering tubes sidewise;

guide and its operfthrough the apand Figure 6 is a schematic diagram of the control system.

Referring now in detail to the drawings and, for the present, to Figure l, a continuous tube mill 1 1 delivers tube blanks rolled on a mandrel bar, to an outlet conveyor 11 composed of spaced rollers. Each mandrel with its tube blank thereon is caused to travel sidewise from the conveyor across a transfer table 12 composed of spaced parallel skids. The mandrel and tube are thus deposited on a distributing conveyor 13 composed of spaced rollers. The rollers of conveyor 13 are driven by motors under any suitable manual or automatic control, in such direction as to feed a bar and the tube blank thereon toward a stripping apparatus indicated generally at 14. The bar is pulled from the tube blank by a chain conveyor y15 driven by a motor 16. The tube blank is delivered sidewise `from the conveyor 13 after removal of the bar, by kickout arms 17 actuated by a crank driven by a motor 18 through reduction gear 19. When lifted from conveyor 13 by the arms 17, the tube blank rolls down a discharge table 20 onto a conveyor 21 which carries the blank on for further processing into a iinished tube.

Our invention relates more particularly to the stripping apparatus 14, the means for operating it and the means for controlling such operating means as well as the motors 116 and 19, which will now be described in detail, referring to Figures 2, 3, and 4. The stripping apparatus proper comprises a standard 22 carried on a base 23 and having a central vertical slot 24 therein. Wear plates 25 are set in the face of the standard adjacent the slot on the side toward conveyor 13. An entry guide 26 of cone shape is split along a plane through its axis into two halves one of which, 26a, is secured to a lever 27 pivoted to the standard on a pin 28 While the other, 2Gb, is secured to standard 22. When the halves of the guide are in juxtaposition as shown in Figure 4, the plane of separation between them is inclined downwardly away Ifrom pin 28. A fluid-pressure cylinder 29 trunnioned to a support 29a has its piston rod pivoted to the outer end oflever 27. On tilting of the lever, the upper half 26B of the entry guide slides over the surfaces of plates 25. Y

The guide halves have slots adjacent their inner end in which are disposed the upper and lower halves or segments 30a and 30b of a transversely split stripper plate 3), the meeting edges of which have semi-circular notches delning a central opening coaxial with the guide. The plane of `division between halves 30a and 30D corresponds to that between the guide halves. The lower half o-f the stripper plate remains in place by its own weight. The upper half is positioned by shoulders 31 formed thereon and in the slot in the upper guide half and is held against removal therefrom by a cross pin 32. The hole formed by the stripper-plate halves is of such size as to embrace the mandrel bar 33 snugly and constitute a sectional barrier to the passage of a tube blank 34 on the bar, which may be opened by operation of cylinder 29 to facilitate sidewise discharge of the blank from conveyor 13 by arms 17 after the bar has been withdrawn from the tube. Thus any fins extruded from the end of the blank into the small clearance between the bar and the edge of the hole in the stripper plate will not interfere with such discharge.

Chain conveyor 15 ywhich serves as a traction device to pull the bar out of a tube while the end of the latter bears against the stripper plate, comprises a pair of chains 35traversing spaced sprockets, one of which is shown at 36. The chains are connected by a plurality of bar-supporting saddles 37. A pair of U-shaped stripper` blocks 38 are equally spaced along the chains and are adapted to engage a turned-down portion 39 of bar 33 which leaves a pulling head 33a at the leading end thereof. Safety stop blocks 40 are also carried by the chains a short distance ahead of each stripper block. A conventional drum-type limit switch 16a (see Figure l) driven by motor 16, stops the latter after a complete stripping cycle, when the blocks 38 and 40 occupy the positions shown in Figure 3. Thus a bar with a tube rblank thereon delivered to conveyor 13 is advanced thereby toward guide Z6 and continues moving until the head of the bar passes through the stripper plate.

For controlling subsequent operations, we provide a switch-operating target or ag 41 adapted to be struck and deected by the head of the bar as it comes through the stripper plate. The bar will ordinarily come to rest shortly thereafter but if not, it will be arrested when its head strikes safety stop block 40. The target comprises a radial arm on a shaft 42 journallcd in bearings 43. These bearings are mounted on a plate 44 secured to base 23. A counterweight arm 45 on the outer end of the shaft tends to hold the target arm in erect position and also actuates a switch 46 having a pivoted operating lever 47. The switch is of known construction and serves to maintain certain contacts closed when its lever is held down by the counterweight. When the latter is raised, the switch lever is tilted upwardly by a spring, opens said contacts and closes others.

Figure shows the details of the kickout arms 17 for discharging tubes sidewise from conveyor 13. As there shown, arms 17 are secured to a line shaft 48 journaled parallel to the conveyor in bearings 49 mounted on base 23 and provided with a crank arm 50. A pitman 51 1s pivoted thereto and to the crank of reduction gear 19.

The operation of our apparatus may best be explained by reference to Figures l and 6. The latter shows diagrammatically certain parts already referred to as well as auxiliary control devices which will be explained as the description of the operation proceeds. As already stated, a mandrel bar with a tube blank thereon, after passing through mill and onto conveyor 11, is caused by known means, under manual or automatic control, to travel across transfer table 12 and onto conveyor 13, whereupon the rotating rollers thereof are driven to advance the bar toward guide 26 and through stripper plate 30. The head 33 of the bar strikes the target arm 41, causing switch 46 to disengage its upper contact 46a and engage its lower contact 46h.

The engagement of contact 46b by the moving element of switch 46 closes an obvious energizing circuit for an initiating relay 52 on a starting panel 53 for motor 16. On instantaneous energization of this relay, other relays and eontactors (not shown) on panel 53 start the motor and bring it up to speed after which the motor continues to operate until stopped by limit switch 16a. As the motor starts to drive the chains of conveyor 15, stripper block 38 approaches the turned-down portion 39 of bar 33, engages the rear face of head 33a and pulls the bar axially away from stripper plate 30. When the end of the blank on the bar strikes the plate it is arrested and is thereby stripped from the bar as the chain continues pulling the latter.

The initial operation of switch 46 by the tilting of target arm 41 also completes an obvious energizing circuit for the operating coil of a relay 54 having front contacts 5S and 56 and a back contact 57. The closing of contact 5S completes a sealing circuit for the relay coil through a control device 58 including a rotary contact finger and a conducting segment engaged thereby. The operation thereof will be explained later. The opening of back contact 57 'deenergizes a normally energized closing coil 591 of a solenoid valve 59 of the four-way non-return type, controlling the admission of air to cylinder 29. When the lower windings is energized, the valve is operated to cause the piston of the cylinder to hold the` movable portions 26a and 30ad of the guide and to starting position,

stripper plate down against portions as shown in Figure 4.

When bar 33 has been pulled completely through the stripper plate and its trailing end passes beyond target arm 41, the latter is restored from tilted to erect position by counterweight 45. This causes switch 46 to disengage contact 46b and engage contact 46a. The disengagement of Contact 46b has no effect since the operation of motor 16 continues under the control of limit switch 16a until the other stop block reaches the position of that shown in Figure 3, and relay 54 is maintained energized through its sealing circuit. The engagement of contact 46a, however, completes an energizing circuit including contact 56 of relay 54, for the opening coil 59a of solenoid valve 59. The resulting operation of the valve causes the piston of cylinder 29 to pull down lever 27 thereby raising the movable portions 26a and 39a of the guide and stripper plate. Simultaneously a circuit is completed through contact 56 for an initiating relay 60 on a starting panel 61 for motor 18. The latter thereupon starts and, by rotating a crank on reduction gear 19, causes arms 17 to be tilted upwardly, thereby delivering the tube blank sidewise from conveyor 13 onto discharge table 20 whence it rolls onto conveyor 21.

After the starting of motor 18, it continues operating, as in the case of motor 16, under the control of a drum limit switch 18ad driven thereby. When the crank of the reduction gear 18 and pitman 51 actuated thereby return the limit switch stops the motor.

The control device 58 is driven by limit switch 18a or may be incorporated directly therein, and is arranged so that the rotary linger will reach the gap in the conducting segment just before the limit switch stops the motor. This breaks the sealing circuit for relay 54 and it immediately opens contacts 5S and 56 and closes contact 57. The opening of contact 56 de-energizes the opening coil 59a of valve 59 and the closing of contact 57 again energizes the closing coil 59b whereby the solenoid valve 26b and 30o thereof is reversed and causes cylinder 29 to lower the movable portions of the guide 26 and stripper plate 30. Thus all p arts of the apparatus are restored to their original positions and are ready to perform another stripping operation.

The advantages of our invention will be largely apparent from the foregoing. In the iirst place, the blank as rolled on the bar is delivered to the stripping apparatus without delay. As soon as the blank and bar reach conveyor 13, they are started toward the stripper. Thereafter the remaining steps in the stripping operation are performed automatically and in close succession whereby the blank is removed from the bar in the least possible time and the apparatus restored to starting condition for receiving the next blank and bar. In the second place, the openability of the stripper plate and guide `eliminates possible difliculty in delivering the blanks sidewise, because of ns extruded at the leading end thereof. The guide, furthermore, insures proper entry of the leading end of the bar into the hole in the stripper plate, thus making it feasible to advance the blank and bar at considerable speed for quick stripping. Finally, the apparatus is simple yet rugged in construction, so as to withstand the rough usage involved in stripping long tubes of substantial size and weight. It is also highly effective in operation and requires but little maintenance beyond routine inspection and lubrication.

Although we have disclosed herein the preferred embodiment of our invention, we intend to cover as well any change or modification therein which may be made without departing from the spirit and scope of the invention.

We claim:

l. In apparatus for stripping a tube from a mandrel bar extending therethrough, the combination with a bell guide split along a plane through its axis inclined at a small angle to the horizontal, means mounting one half of said guide for movement from and to the other half thereof and means xedly mounting said other half, the two halves of the guide having slots therein normal to the faxis or" the guide, of a stripper plate disposed in said slots having an opening therethrough dimensioned to admit the bar but not the tube, said plate being divided on the same plane as said guide, and means securing one portion of said plate to the movable half of the guide for movement therewith, the other portion of said plate being seated in said other half of said guide.

2. In apparatus for stripping a tube from a mandrel bar, said apparatus including a roller conveyor for axially moving a bar with ya tube thereon, a stripper plate having a circular opening therein dimensioned to admit said bar but not the tube, said plate being normally positioned with its opening coaxial with a -tube disposed on the conveyor and being composed of two segments meeting along a dividing plane extending transversely of said opening, fixed means mounting one of said segments in normal position, a pivoted arm mounting the other segment for angular movement away from said one of said segments, a split conical guide extending toward the conveyor from one side of said plate, said guide comprising two coacting segmental portions including a Xed portion and a portion mounted on said arm and thereby movable with the 6 said other segment of said plate between closed and open position.

3. The apparatus deiined by claim 2 characterized by said guide portions having recesses formed therein adapted removably to accommodate said segments, respectively, in positions such that they are in cooperative relation when said guide is closed.

References Cited in the le of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,901,818 September 1, 1959 Walter A. Lindstrom et al.,

It is hereby certified that error appears in the printed specification of the above numbered patent .requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line A, for' "mill 11" read mill lO column 6, line 1l, list oi references cited, for' the patent number "1,342,762" read n., 1,342,763 D Signed and sealed this 8th day ofy March 1960.

(SEAL) ttest:

"ARL H9 AXLINE ttesting Officer ROBERT C. WATSON Commissioner of Patents 

